U.S. Pat. No. 2,529,106 relates to a combined hood and respirator where the respirator device is externally connected to a hood comprising several fabric sectional panels stitched together.
U.S. Pat. No. 3,458,864 relates to a simple protective hood containing a front plastic window for vision purposes where the hood includes an outer skirt and an inner annular flap. The various parts of the fabric hood are sewn together.
U.S. Pat. No. 4,032,991 relates to a protection device containing an air-tight envelope made of fire resistant transparent sheet plastic material and encloses a premoistened porous face mask secured thereto. The device is rendered into the operative condition by opening the envelope which converts to a head cap for covering head and eyes of the wearer and extending the face mask out of the envelope whereby the mask extends downwardly from the cap over the nose and mouth of the wearer to afford protection against smoke and noxious fume inhalation.
U.S. Pat. No. 4,146,025 relates to a device for testing the tightness of fit of a gas mask which has a tubular respiratory air inlet and a tubular exhaling air outlet, which is applied over the face of a wearer, comprising a bag-like headpiece which is engageable over the wearer's head and is preferably made of a transparent material, such as plastic, and which is provided with an opening for the wearer's neck and an opening for the tubular air inlet of the gas mask with a resilient rim for tightly engaging these parts when the headpiece is positioned on the wearer's head.
Other air supplied hoods are shown in U.S. Pat. Nos. 4,411,264, and 4,466,432, where respirator air is supplied from an external source for breathing purposes.
U.S. Pat. No. 4,484,575 pertains to an air supplied respiratory hood containing a curved optical transparent lens. The hood is supported overhead by a forehead engaging board. Air under pressure is supplied to the interior of the hood through a neck engaging, permanently formed, tubular ruff having front apertures 46 for supplying air to the wearer (FIGS. 13 and 14). An annular elastic band is located within the preformed ruff to maintain intimate contact with the neck. The hood is further fitted with an annular collar 54 for interconnecting the hood structure with a protective suit.
U.S. Pat. No. 4,619,254, relates to a protective hood fitted with a respirator device where the hood includes a so-called ruff, comprising an annular rigid tube disposed approximate to the chin area which provides respirable air to a respirator means inside the hood.
U.S. Pat. No. 4,768,235, relates to a cold weather mask and hood made of a flexible insulating layered material which covers the wearer's entire head, shoulders and upper chest. A partially detachable face portion contains a lens receptacle which holds removable lends. An air intake hose provides warm, fresh air for inhalation, and an exhaust tube is used for exhalation. The exhaust tube contains ridges which hold the mask away from the lower face to form an air pocket.
In U.S. Pat. No. 4,870,959, a simple one-piece head mask is shown comprising a plastic enclosure for the head only and containing a filtered opening in the mouth area for breathing.